In recent years, in order to cure an eye disease such as a cataract, a surgical operation in which the crystalline lens within an eye is replaced with an intraocular lens (an artificial crystalline lens) is often adopted. As an example of the aforementioned surgical operation, phacoemulsification and aspiration (PEA), in which the crystalline lens in the diseased part is fragmented using ultrasonic vibration and the emulsified crystalline lens is aspirated, is commonly used. In this surgical operation, an ultrasonic handpiece (hereinafter simply referred to as “the handpiece” as well), which is an ultrasonic emulsification and aspiration device, is used. The handpiece includes a rod-shaped main body, which is supported by the operator's hand. A transducer that generates ultrasonic vibrations, and a horn that amplifies the ultrasonic vibrations generated by the transducer, are built into the main body. A fragmentation tip for fragmenting and emulsifying a crystalline lens is attached to a front end of the main body. The tube-shaped fragmentation tip is coupled to the horn, and is able to provide ultrasonic vibrations to the crystalline lens that is to be subjected to the surgical operation.
In the surgical operation, the crystalline lens is fragmented by ultrasonic vibrations while a perfusate is supplied into the anterior chamber of the eye. The crystalline lens is emulsified by ultrasonic vibrations, and is discharged to the outside together with the perfusate, via an aspiration channel provided in the handpiece. However, part of the nucleus of the crystalline lens is discharged as fragments (nucleus fragments), together with the perfusate.